1. Field of the Invention
The present invention relates to 4-hydroxytetrahydropyran-2-one and 3,5-dihydroxyheptanoic acid derivatives, which are useful as cholesterol reducing agents as well as lipid reducing agents since the 4-hydroxytetrahydropyran-2-one and 3,5-dihydroxyheptanoic acid derivatives have a strong inhibition of effect on 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (hereinafter referred to as HMG-CoA reductase).
The present invention alto relates to intermediates for synthesizing the above derivatives which are useful as cholesterol reducing agents or lipid reducing agents.
2. Discussion of Background
As a remedy for reducing blood cholesterol which works as one of significant factors relating to the development of arteriosclerosis, ML-236B has been discovered which inhibits the biosynthesis of cholesterol by the competitive inhibition of the effect of HMG-CoA reductase, which serves as a rate-determining enzyme for the formation of cholesterol, thereby reducing the level of the blood cholesterol (refer to Japanese Laid-Open Patent Application 50-155690). ML-236B is a compound having a 6-substituted-4-hydroxytetrahydropyran-2-one skeleton. After the discovery of the ML-236B, various compounds with a 4-hydroxytetrahydropyran-2-one skeleton, having a blood-lipid-reducing effect, have been proposed (refer to T.-J. Lee, Trends in Pharmacol. Scie., 8 (1), 4420 (1987), and Drugs of the Future 12 (5), (1987)).
Furthermore, it is considered that a compound which has an antioxidation effect and therefore inhibits the formation of peroxidized lipids will also be useful as a remedy for arteriosclerosis, and it is reported that vitamin E and probucol have such effects.